Why does gravity affect time?

  • Thread starter adimantium
  • Start date
  • #1
13
0

Main Question or Discussion Point

I understand that Einstein had the idea of space as a 2 dimensional grid with "planets" sitting of the grid, stretching it out, but I don't get why this affects time.
 

Answers and Replies

  • #3
phinds
Science Advisor
Insights Author
Gold Member
2019 Award
16,080
6,051
Why does gravity affect time?
Gravity doesn't affect "time", it affects "spacetime". This is not just semantics. There are plenty of place on the internet to read about this.
 
  • #4
A.T.
Science Advisor
10,179
1,870
I understand that Einstein had the idea of space as a 2 dimensional grid with "planets" sitting of the grid, stretching it out, but I don't get why this affects time.
Think about it: If gravity was just distortion of space, how would it ever affect objects that are initially at rest in space? The distortion of spatial distances can only affect objects which already move through space. But why would an apple start falling from rest. Obviously the time dimension must be distorted too, to affect the apple that initially advances only through time. See animation below:

https://www.youtube.com/watch?v=DdC0QN6f3G4

See also this pictures that visualize the different effects of gravity:

http://www.physics.ucla.edu/demoweb..._and_general_relativity/curved_spacetime.html
 
  • Like
Likes 1 person

Related Threads on Why does gravity affect time?

Replies
16
Views
3K
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
5
Views
542
  • Last Post
Replies
11
Views
12K
Replies
7
Views
5K
  • Last Post
Replies
2
Views
1K
Replies
23
Views
245
Replies
7
Views
2K
Replies
2
Views
11K
Top